Pipeline repairs are becoming more common as existing pipe networks age. In particular, there is a need in underwater pipeline repairs for a simple, reliable, weld-free mechanical connector that can be employed with minimum human intervention.
To address the foregoing need for devices to affect underwater pipeline repairs, there has been developed several connectors that do not require welds or flange bolting. For examples, U.S. Pat. Nos. 5,056,830 and 5,209,522 disclose a flange coupling that is engaged by slips instead of bolts.
Pending U.S. patent application Ser. No. 08/106,684, filed Aug. 16 1993, entitled Weldless Pipe Repair Apparatus and Method, discloses a weldless pipe repair apparatus comprising a remote-operated underwater pipe connector. The remote-operated connector grips and seals about a stand of underwater pipe by hydraulicly actuating pistons within the connector which, in turn, actuate gripping slips and an expandable seal. The foregoing invention is a substantial improvement over prior devices. However, the displacement of the pistons and particularly hydraulic pistons are difficult to control making the gripping and sealing force unpredictable and unadjustable. Thus, there has arisen a need for controlling and/or indicating the displacement of the pistons.